Apparatus for the manufacture of sheets of asbestos cement or the like at a high hourly production rate

ABSTRACT

Apparatus for the manufacture of sheets of asbestos cement, in which a large asbestos sheet is cut, in a first station, into standard size sheets, while the large sheet is conveyed by conveyor belts towards the first station. At one side of the first station four tracks for trollies are arranged parallel to the direction of advancement of the large asbestos sheet, two of the trollies carry patterns and the other trollies, nearer to the first station carry mixed packs of patterns and asbestos cement sheets. A bridge structure extends above the first station and the tracks in a direction transverse to the tracks. A truck is movable along the bridge structure. The truck carries suction units and boxes which take up and deposit, in preestablished intervals, the patterns and the asbestos cement sheet on the trollies.

Unite States Patent [72] Inventor Dante Colliva Bologna, Italy [21] Appl. No. 790,549 [22] Filed Jan. 13, 1969 [45] Patented Oct. 26, 1971 [73] Assignee Riva Calzoni S.p.A.

Milan, Italy [32] Priority Jan. 22, 1968 [33] Italy [31] 11855 A/68 [54] APPARATUS FOR THE MANUFACTURE OF SHEETS OF ASBESTOS CEMENT OR THE LIKE, AT A HIGH HOURLY PRODUCTION RATE 6 Claims, 7 Drawing Figs.

[52] U.S.Cl 156/585 {51] 1nt.Cl B31t 1/00 [50] Field otSearch 156/585, 5 86, 5 89 [56] References Cited UNITED STATES PATENTS 2,589,379 3/1952 Herzog 156/585 2,655,196 10/1953 Magnani 156/585 FOREIGN PATENTS 15.5,267 3/1956 Germany 156/585 Primary Examiner--Benjamin A. Borchelt Assistant ExaminerC. T. Jordan Attorneys-Guido Modiano and Albert Josif ABSTRACT: Apparatus for the manufacture of sheets of asbestos cement, in which a large asbestos sheet is cut, in a first station, into standard size sheets, while the large sheet is conveyed by conveyor belts towards the first station. At one side of the first station four tracks for trollies are arranged parallel to the direction of advancement of the large asbestos sheet, two of the trollies carry patterns and the other trollies, nearer to the first station carry mixed packs of patterns and asbestos cement sheets. A bridge structure extends above the first station and the tracks in a direction transverse to the tracks. A truck is movable along the bridge structure. The truck carries suction units and boxes which take up and deposit, in preestablished intervals, the patterns and the asbestos cement sheet on the trollies.

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Dan re COLUVQ BY WML , Hqen APPARATUS FOR THE MANUFACTURE OF SHEETS OF ASBESTOS CEMENT OR THE LIKE, AT A HIGH HOURLY PRODUCTION RATE BACKGROUND-OF THE INVENTION This invention relates to an apparatus for the manufacture of sheets of asbestos cement or the like at a high hourly production rate.

It is well known that in order to obtain a high hourly production rate of asbestos cement sheets, either in the form of flat or corrugated sheets, various improved automatic apparatuses have been suggested in order to increase the rate of production.

However, in practice, for a given apparatus it has not been possible to exceed certain production rates because the speeds of the various working parts must be maintained within determined limits in order to avoid the obtainment of imperfectly finished asbestos cement sheets.

Moreover a moulding machine also has productivity limits which it is not possible to exceed and yet obtain a product which conforms with the standard and test requirements. For a given width of the asbestos cement sheet there is hence a productivity limit.

It has consequently been attempted to develop apparatus which simultaneously produces two sheets of asbestos cement, but this has not provided completely satisfactory results because considerable difficulties have been encountered during the phase of lifting the formed asbestos cement sheets which are standing in side-by-side relationship.

In fact, because of their dimensions, it is necessary that the two lifting mechanisms employed operate alternately above the lifting belt. Consequently, a large part of the advantage of reduction of manufacturing time with respect to the conventional manufacturing systems is lost.

In addition the overall cost of the plant is so high that in practice it is not convenient to manufacture such high production apparatus.

The main object of this invention is that of obviating the disadvantages mentioned above relative to conventional systems for the manufacture of asbestos cement sheets, by providing an apparatus for the manufacture of asbestos cement sheets and the like, either in the form of corrugated or flat sheets, which has a production capacity approximately double that of conventional apparatus, with an appreciable reduction in the installation and operation cost with respect to that obtained by simply doubling a conventional apparatus.

Another object of the invention is that of providing a large scale apparatus which permits an appreciable reduction of waste scrap and at the same time ensures a high quality production.

SUMMARY OF THE INVENTION .According to the invention there is provided an apparatus for the manufacture of asbestos cement sheets, which comprises a forming unit for forming sheets of asbestos cement, conveyor means arranged at the outlet of said forming unit for conveying the asbestos cement sheets produced by said forming unit, cutter means arranged adjacent said conveyor means for cutting each of said asbestos cement sheets into a plurality of subsheets, said cutter means being arranged to cut said sheets in the direction of advancement of said conveyor means, first and second trolley guide tracks arranged on one side of said conveyor means and arranged to extend parallel to the direction of advancement of said conveyor means, first trolley means displaceably mounted on said first trolley guide tracks, second trolley means displaceably mounted on said second trolley guide tracks, a fixed bridge structure arranged transversely above said conveyor means and said first and second trolley guide tracks, a truck slidably mounted on said fixed bridge structure, a plurality of suction boxes mounted on said truck, a plurality of suction units mounted on said track, said truck being cyclically arranged to slide on said fixed bridge structure between a first position and a second position, in said first position said suction units are arranged to raise a set of side-by-side asbestos cement subsheets carried by said conveyor means and said suction boxes are arranged to deposit on said first trolley means a set of patterns previously raised from said second trolley means, in said second position said suction units are arranged to deposit said set of subsheets onto said first trolley means and said suction boxes are arranged to raise a set of patterns from said second trolley means; the arrangement being such that a. plurality of piles of alternate sets of patterns and subsheets is formed in said first trolley means.

BRIEF DESCRIPTION OF THE DRAWINGS paratus through the line lII--III of FIG. ll;

FIGS. 4 and 5 show in detail, to an enllarged scale, suction mechanisms for the production of corrugated asbestos cement sheets, in an arrangement for picking up the sheets and for corrugating and depositing them respectively;

FIGS. 6 and 7 show, in detail, to an enlarged scale, flat sheet suction boxes, arranged for picking up and depositing flat asbestos cement sheets respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment of the apparatus for the manufacture of asbestos cement sheets or the like according to the invention illustrated in the FIGS. is arranged for the simultaneous production of two corrugated or flat sheets.

With reference to the figures of the accompanying drawing the apparatus comprises an asbestos cement sheet forming unit it of the conventional type which has, however, a width about double that of a normal forming unit so that a sheet of normal length having a width double that of a normal sheet may be obtained. Downstream of the forming unit 1 there is arranged a conveyor belt 2 which is followed by a lifting and cutting belt 3 defining a first station.

Between said belts 2 and 3 there is arranged a central cutter 4 which is arranged to execute a middle cut so as to divide the moulded asbestos cement sheet into two sheets and two lateral cutters 5 which trim the two lateral edges of the formed sheet. The cutters 4 and 5 operate during the transfer of the sheet from the belt 2 to the belt 3.

On one side of the belt 3 in a second station and parallel to its direction of advancement, there are arranged two parallel pairs of tracks 6 on which trollies 7, intended to carry the mixed packs formed from alternate patterns and asbestos cement sheets, are arranged to run. At the side of the tracks 6, and on the same side of the belt 3, are arranged two other parallel pairs of tracks 8 on which trollies 9 intended to carry the moulding patterns are arranged to run. The two pairs of tracks 6 are arranged close together, as is also the case with the lines 8, so that the control devices, especially the controls of the members carried by the truck I2 (which will be described hereinafter) can be arranged as a single unit. The devices for actuating the trollies are diagrammatically indicated by reference numeral 10 in FTGS. 2 and 3, these devices being independent from one another.

Above the tracks 6 and 8 and the belt 3 there is arranged a transverse bridge structure 11 which carries a sliding truck 12. Said truck 12 supports a pair of suction boxes 14 which are intended to lift and deposit the patterns, and a pair of suction units I5 which are intended to lift and deposit the asbestos cement sheets, by means of hydraulic jacks l3 and lateral guides 130. In the case of production of corrugated sheets, said suction units 15 are provided with a device for forming the corrugations of the sheets, for example of the type described in the Italian Pat. No. 785,640 of the same applicant.

n the side facing the belt 3, the truck 12 carries a cutting unit 16 which may comprise a central cutter 17 and two lateral cutters 18, or a greater number of cutters arranged as described in the Italian Pat. No. 784,764 of the same applicant.

As shown in FIGS. 4 and 5, the suction units 15 for lifting and depositing the corrugated type asbestos cement sheets comprise transoms 19 attached to the guides 130. A number of parallel sucker element 20 are provided in each suction unit 15 and are secured to sleeves 21 which slide on horizontal guides 22 secured parallel to said transoms 19. The two suction units 15 are arranged side by side on the truck 12 and comprise, at the adjacent sections, terminal sleeves 21a, which carry sucker elements 20a for the terminal portions of the asbestos cement sheets and are upwardly provided with projections 23. Said projections 23 are connected to means for the displacement of the sleeves for the corrugation of the sheets. More precisely, in each suction unit 15 there is provided at least one hydraulic jack 24 whose rod is connected to said projection 23 and whose body is attached to another projection 25 fast with the support structure of the guides 22 on the side opposite to that on which the projections 23 are arranged.

When the rods of the jacks 24 are in the position of maximum extension, the sleeves 21 are spaced apart (FIG. 4) so that the sucker elements 20 are in a position for lifting a sheet from the belt 3. When the rods of the jacks 24 are caused to retract into the respective jack cylinders (see FIG. the sucker elements 20 are close to each other so as to be able to form the corrugations of the previously lifted asbestos cement sheet.

The two suction units are arranged symmetrically so that as the edges of the two sheets which were in contact have only been cut, they move away from each other in the corrugation phase by a distance equal to double the difference between the width of the sheet when it is flat and the width of the sheet when it is corrugated. This is designed to ensure a distance between the axes of the sheets such as to allow said sheets to be deposited onto the trollies 7 carried on the tracks 6.

It is evident in fact that said trollies 7 cannot be brought close together beyond a certain limit and on the other hand the simple shrinkage in width of the sheets due to their corrugations may not be sufficient to enable them to be deposited onto said trollies 7.

In certain cases it may be necessary to increase the distance between the axes of the sheets still further, in which case the outer sleeves 21b of the suction units 15 can be locked or unlocked on the guides 22, means being provided for sliding linkage 2l between the sleeves 21b and the lateral support structures of the guides 22. An arrangement is thus obtained by means of which it is possible to move the asbestos cement sheets still further outwards, during the corrugation phase, by a length 26 (FIG. 4), by unlocking the sleeves 21b. (The locking means for the sleeves 21b are not shown). The arrangement is designed to ensure that the center of the corrugated sheets shall be disposed along the fixed center line of the trollies 7, irrespective of the type of corrugation effected. The distance 26 can hence be adjusted according to the type of corrugation. When it is required to form and stack flat sheets, it is possible to replace the suction units 15 with other suction units 15a which comprise flat suction boxes 27 (FIGS. 6 and 7). The replacement is effected by unlocking the suction units 15 at the guides 13a and successively locking in the same place the transoms 19a of the suction units 15a. This replacement can be carried out rapidly since the fixing is effected by means of bolts or the like.

In each suction unit 15a the relative suction box 27 is mounted so that it moves horizontally, the suction boxes 27 being supported by sleeves 28 which slide on the guides 22a fast with said transoms 19a.

In the case of flat asbestos cement sheets evidently the adjacent edges of the sheets do not move away from each other due to the effect of corrugation, and consequently in order to ensure that the center line of each flat sheet corresponds with the center line of the trollies, it is necessary to make the suction boxes 27 carry out a longer stroke than that provided in the case of corrugated sheets.

For the displacement of the suction boxes 27, horizontal hydraulic jacks 29 are provided whose bodies are secured to said transoms 19a and whose rods are secured to sleeves 28 which carry the suction boxes 27. In this way it is possible to move said suction boxes from the lifting position of FIG. 6 to the depositing position of FIG. 7, and vice versa.

The displacement of said suction boxes 27 is inversely proportional to the width of the flat asbestos cement sheets. Consequently a series of stroke end stops designed to limit the stroke 30, or, alternatively, other adjustment means are provided on the rods of the hydraulic jacks 29 to correspond to the series of widths on the flat sheets which it is required to form.

Both for the production of flat sheets and the production of corrugated sheets, the transoms 19a and 19, respectively, can move independently upwards or downwards so that the suction units 15 and 15a, respectively, can adapt themselves to the pile of the various trollies and therefore the heights of the piles may be different from one another. The movement away from each other of the two sheets simultaneously produced is effected by movement of only the lower parts of the suction units, relative to the transoms Band 190.

The suction boxes 14 also move independently upwards and downwards in order to adapt themselves to the different heights of the piles of patterns.

The working of the apparatus according to the invention will now be described.

After the asbestos cement sheet produced by the forming mechanism 1 has been divided into two pieces by the action of the central cutter 4 and simultaneous finishing of the edges by means of the cutters 5, the said two pieces arrive on the belt 3 where the truck 12, which is arranged transversely of the belt 3, trims the front edges of the sheets, by means of the lateral cutters l8, and if necessary executes a middle cut by means of the cutter 17. When the two suction units 15 reach the end of their stroke, they descend onto the sheets in the arrangement shown in FIG. 4, where the sucker elements are spaced apart, while the suction boxes 14 descend onto the trollies of mixed packs 7 in order to deposit a pattern onto each pack.

Successively the suction system is actuated so that the suction units 15 initiate the phase of lifting of the two flat sheets lying on the belt 3, while the suction ceases in the suction boxes 14 which thus deposit the patterns onto the trollies 7.

The suction units 15 and the suction boxes 14 are then raised while the truck 12 travels towards the left of FIG. 3, until it reaches the position shown in the same figure.

During this movement, the corrugation of the two sheets is effected by means of bringing the sucker elements close together so as to assume the arrangement shown in FIG. 5. In this manner the sheets are corrugated and consequently move away from each other to a maximum distance which also include the distance 26 (FIG. 4) due to the movement of the unlocked sleeves 21b along the guides 22.

At this point the suction units 15 and the suction boxes 14 are lowered onto the trollies 7 and 9 for depositing the already corrugated sheets and for lifting two new patterns.

Obviously if a smaller reciprocal movement apart of the corrugated sheets is sufficient, then the sleeves 21b are locked onto the guides 22 in the position shown in FIG. 5, or their stroke is suitably adjusted.

In any case a distance between the centerlines of the two sheets produced must be obtained which is equal to the distance between the centerlines of the tracks 6 (the distance between the centerlines of the boxes 14 is fixes and is equal to the distance between the centerlines of the tracks 8 and the tracks 6).

In this way these distances can be made to correspond to the distance between the trollies 7 and 9 of the tracks 6 and 8, respectively, this latter distance being determined by the dimension requirements of the patterns and sheets and by the spaces necessary for lifting trollies by means of cranes or the platform cars for carrying mixed packs with their relative hooking devices. The said distance between the centers can thus be fixed as required at the design stage irrespective of the type of corrugated or flat sheet because of the possibility of further movements guaranteed by the stroke length 26 for the corrugated mechanisms, and because of the possibility of sliding the suction boxes 27 for the flat sheets.

As may be noted, the central cut executed by the cutter 4 on the sheet coming from the moulding mechanism 1 takes place without the removal of any material and hence without giving rise to any central selvage strip. This allows a considerable reduction in waste.

After depositing the corrugated sheets and lifting the patterns, inverse movements to those described above are effected due to the movement of the truck 12 towards the right (referring to FIG. 3) and the successive lowering of the suction units onto the belt 3 and the suction boxes 14 onto the trollies 7.

The phases described above are then carried out with completely analogous operation, for the lifting, formation and depositing of two other corrugated sheets.

If it is required to produce flat sheets, the suction units 15 are replaced with the suction units 150 as previously described, after which the apparatus operates substantially as previously described.

As may be noted, the apparatus according to the invention enables the obtainment of a production double that obtainable with an apparatus of conventional type, with considerably reduced installation and operation costs. in fact the apparatus according to the invention the various controls can be grouped together, so reducing the number of devices necessary.

As a variation the apparatus can be provided for the simultaneous production of three sheets, by providing three suction units, three suction boxes, three pairs of tracks 6 and three pairs of tracks 9.

In this case the central suction unit would be provided at its base with corrugating means which move towards its middle line, while the other two suction units would move laterally.

l claim:

1. An apparatus for the manufacture of sheets of asbestos cement, which includes a first station, a conveyor means for taking up and cooperating in cutting into standard size sheets a large asbestos cement sheet coming from an asbestos cement sheet forming mechanism and reaching said first station, at least two tracks for patterns carrying trollies, at least two tracks for trollies for mixed packs of patterns and asbestos cement sheets, suction boxes for patterns, suction units for taking up in a first station and depositing in a second station said standard size sheets on said trollies for mixed packs, and a fixed bridge structure movably carrying said suction boxes for patterns and said suction units for said standard size sheets, wherein, according to the improvement, the apparatus comprises all said tracks for trollies arranged on one side of said conveyor means, said bridge structure being placed transverse above said tracks and said conveyor means, a sliding truck for carrying at least two of said suction boxes for patterns and at least two of said suction units for said standard size sheets, said sliding truck being mounted on said bridge, cutting means for producing at least one cut over the whole large sheet in its direction of advancement thereby to obtain said standard size sheets, said sliding truck moving said suction boxes and said suction units along said bridge structure from one end position in which said suction units reach said first. station to another end position in which said suction units reach said second station, and vice versa, power means connected with said suction units for moving at least two adjacent of said suction units apart from each other before said suction units de s it said standard size sheets on said trollies for mixed pac s in said second station.

2. An apparatus as claimed in claim I, wherein each of said suction units comprises substantially horizontal guides, sleeves arranged to slide on said guides, a plurality of sucker elements fixed to said sleeves, control means for said sleeves to move them towards each other thereby effecting corrugation of said standard size sheets and move them apart reciprocally, said control means being arranged to move said sleeves towards one end of said guides during the corrugation of said sheets, in order to move thereby the simultaneously produced contiguous sheets away from each other.

3. An apparatus as claimed in claim 2, further comprising removable locking means to lock at least one of said sleeves on said guides in order to vary the stroke of movement of said suction units.

4. An apparatus as claimed in claim 1, wherein said suction units include substitute guides and suction boxes mounted on said substitute guides so that they move in a substantially horizontal direction for the production of flat asbestos cement sheets and hydraulic jack control means attached to said suction boxes.

5. An apparatus as claimed in claim 4, which includes stroke end stop members for varying the stroke limits of said suction boxes in relation to the width of the asbestos cement sheets produced.

6. An apparatus as claimed in claim 1, wherein said power means include control members controlling the movement of said suction units thereby to move in opposite directions apart from each other said suction units prior to depositing said standard size sheets on said trollies for mixed packs, and to maintain said suction units in a closeup position when said suction units reach said first station. 

2. An apparatus as claimed in claim 1, wherein each of said suction units comprises substantially horizontal guides, sleeves arranged to slide on said guides, a plurality of sucker elements fixed to said sleeves, control means for said sleeves to move them towards each other thereby effecting corrugation of said standard size sheets and move them apart reciprocally, said control means being arranged to move said sleeves towards one end of said guides during the corrugation of said sheets, in order to move thereby the simultaneously produced contiguous sheets away from each other.
 3. An apparatus as claimed in claim 2, further comprising removable locking means to lock at least one of said sleeves on said guides in order to vary the stroke of movement of said suction units.
 4. An apparatus as claimed in claim 1, wherein said suction units include substitute guides and suction boxes mounted on said substitute guides so that they move in a substantially horizontal direction for the production of flat asbestos cement sheets and hydraulic jack control means attached to said suction boxes.
 5. An apparatus as claimed in claim 4, which includes stroke end stop members for varying the stroke limits of said suction boxes in relation to the width of the asbestos cement sheets produced.
 6. An apparatus as claimed in claim 1, wherein said power means include control members controlling the movement of said suction units thereby to move in opposite directions apart from each other said suction units prior to depositing said standard size sheets on said trollies for mixed packs, and to maintain said suction units in a closeup position when said suction units reach said first station. 